Few pilots simply operate their aircraft. In addition to causing aircraft to operate as desired from instant to instant, pilots deal with numerous avionic systems. Through these systems pilots gain intelligence letting them know what to do to travel safely from point A to point B and to avoid collisions. Voice communication radios, navigation systems, compasses, altimeters and the like represent a few of such avionic systems.
In accordance with current practices, collision avoidance functions take place primarily over radios through voice communications with air traffic controllers. In a crowded airspace, a virtually continuous stream of conversations with air traffic controllers manages collision avoidance for the aircraft in the airspace. The air traffic controllers base their communications upon information generated by a massive infrastructure of collision avoidance systems. The collision avoidance infrastructure includes radar systems and a population of aircraft-mounted transponders.
The number and diversity of these aviation-related systems provides a complicated aircraft cockpit environment. Pilots digest vast amounts of visual and audible data, much of which is distracting and has little or no direct bearing upon pilots' immediate informational needs. Often times, verbal communications are misunderstood. At best, when verbal instructions are misunderstood from a radio they are repeated, which throws even more audible information at all pilots tuned to that frequency. In the worst cast, when verbal instructions are misunderstood pilots may err in following the instructions, leading to seriously unsafe conditions. The flood of verbal and visual information available to pilots and the complication of avionic systems leads to pilot fatigue, pilot error and generally unsafe aircraft operating conditions.
Industry experts have long recognized that additional or different types of aviation systems might improve airspace safety, and many alternate systems have been proposed. One desirable alternate solution to collision avoidance gives pilots visual information, such as on a video display terminal, describing the location of nearby aircraft. Pilots are ultimately responsible for the safe operation of their aircraft. This alternate collision avoidance system is desirable because it allows pilots to share with traffic controllers in making decisions regarding collision avoidance. Moreover, this solution lessens the workload and responsibilities placed on air traffic controllers.
While desirable in theory, the conventional proposals for this type of collision avoidance solution have two serious drawbacks. First, they typically place yet another avionic system in the cockpit to further burden pilots with data. Thus, these conventional proposals advocate the use of systems which typically complicate rather than simplify the cockpit. Second, these types of collision avoidance systems often require substantially all aircraft to be equipped with the system before a significant safety benefit may result. Often times, proposed alternate collision avoidance systems generate particularly unsafe conditions when nearby aircraft are not equipped with the alternate system.
This second problem is an extremely serious drawback. A massive infrastructure of radio systems, transponder systems, radar systems, navigation systems and the like currently exists in a vast number of aircraft, airports and other control facilities. Alternate avionic infrastructures cannot be brought instantly "on-line." In other words, the entire aviation industry cannot simply and instantly overcome the massive cost, installation, testing and troubleshooting problems posed by an alternate system's infrastructure. Consequently, alternate systems must co-exist with old systems, perhaps for a considerable period of time. When comparing existing and alternate systems, the existing systems are useful because the required infrastructure is already in place, and the results are still tolerable, albeit far less than desirable. The massive costs of an alternate infrastructure coupled with a lack of benefit, and even possible harm, until substantially all aircraft and facilities are equipped with the systems that link them in the alternate infrastructure and the additional cockpit complication imposed by an alternate system cause such alternate systems to be un-implementable for all practical purposes.